Walter s



(No Model.)

W. S. PIERCE. GALGINING A1\PARAT.US.

N0. 530,125. Patented Dec. 4, 1894.

yawmwboz 8 1g aHIozum J' UNITED- STATES PATENT El -ICE,

W'ALTER S. PIERCE, OF NEW YORK, N.,Y.

CALCINING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 530,125, dated December4, 1894.

Application filed March 6, 1893. Serial No. 464,732, (No model.)

To aZZ whom it may concern.-

Be it known that 'I, WALTER S. PIERCE, a

' citizen of the United States, residing at New York city, in the countyand State of New York, have invented a certain new and usefulImprovement in Oalcining Apparatus, of which the following is aspecification.

My invention relates to such calcining apparatus as is "provided with arotatable cyl-' inder, and consists in combining with such cylinder aretort in. which the treatment of {the material, partially carried outin the cylinder, is completed. p

The object of this partof my invention is a device capable of affordingthe material undergoing treatment a varying degree of heat as it passesfrom the entrance to the exit end thereof; and further to increase thedurability of the apparatus by providing that the and tumbledsufficiently to insure good treatment without oaking or burning; and inproviding at the discharge end of the apparatus a conveyer which willcarry off the material after it leaves the retort in a regulatedway.

The object of this portion of my invention is to provide means wherebythere will be insured a regular and uniform treatment of material; itbeing obvious that by providing a feeding device at the entrance end ofthe rotatable cylinder, which regulates the quantity of materialdelivered, and a conveying device at the exit end of the apparatus,which is regulated with reference to the feeding device, the materialwill be caused to pass through the calcining apparatus in regulatedquantities, practically uniform at any instant of time, and hence thatthe material will relar and uniform product.

be specifically pointed out in the claims.

In the accompanying drawings, forming part of" this specification,Figure l is a side elevation, in section, of my improved appa: ratus.Fig. 2 is an elevation thereoflooking in the direction of the arrow,Fig. 1; and Fig.

3 is a section on the line 3-3, Fig. 1, showing the retort.

A represents the masonry which supports the apparatus.

B represents the calcining cylinder, two of 6 5 which may be employed,as shown in Fig. 2. 0 represents a retort of the usual material, and Drepresents a furnace.

The cylinder B, as shown, is supported on a shaft 1) by spiders c, theshaft being jour- 0 through the cylinder, and at the same time tothoroughly tumble and agitate the same. A fuller description of arotatable cylinder combined with such blades and ribs will be found inan application filed by me on the 31st 'day of October, 1891, Serial No.410,482. I do not, however, in the present application intend to limitmy apparatus to the use of these blades and ribs, as other feedingdevices for the cylinder may be in existence or be devised which willanswer to attain the object now in view. At each end the cylinder isfitted into a plate of metal E, E which serves to receive and hold bysuitable bolts or otherwise a drum or cap F, F, which closes thecylinder ends, and at the same time af- 5 into a suitable box or otherreceptacle, which receptacle may be provided with a pipe leading to theatmosphere. I have not shown this apparatus, as its construction will beobvious. .The object is to carry off the steam H 4 MM.

generated at the entrance end of the apparatus from the materialundergoingtreatment and to catch in the box or receptacle above referredto the particles which are carried off by the steam, afterward lettingthe steam exit to the atmosphere. Asmall doort in the cap F may beemployed to withdraw the material that accumulates therein.

G is a hopper, which furnishes material to a screw-conveyer H, whichfeeds the same in regulated quantities to the feed-pipe I, whichdelivers the same into the cylinder, as shown. At the exit end of thecylinder, a pipe J conveys the material treated in the calciningcylinder to the retort G, where, after treatment, it is carried off inregulated quantities by the screw-conveyor K. It will be seen that therewill be a regular flowot' material through the apparatus, governed bythe relation of the feed and discharge conveyers, which in turn may beregulated by moving them faster or slower. Gone pulleys are preferablefor thus governing the speeds of the conveyers.

'lhe retort cylinder 0 is shown as inclined with relation to thecylinder B, and I prefer this arrangement. It rests at one end upon anarch or deflector L, which runs under the cylinders B from the exit tonear the entrance end thereof. At the other end, the retort rests on aportion of the masonry work A. Over the retort (J is an arched wall orde' fleetor M, and under it an arch or deflector N, the latterprotecting the said retort from the direct flames of the furnace, andthe former serving to insure a circulation of heat around the saidretort. The manner of supporting the wall M is best shown in Fig. 3.

The heated gases generated by the furnace D pass, as shown by thearrows, around the arch N, and into the space between it and the retortO, and around said retort into the space between the same and the wallM, thence pass the sides of the retort Fig. 3 into the flue beneath thearch L to near the entrance end of the cylinder B, thence around saidcylinder and out at the stack P. It will thus be seen that the materialto be treated, while in the calcining cylinder, is subjected to a lowerdegree of heat than while in the retort; that the cylinder is protectedfrom being burned out, and the material is gradually subjected toincreasing heat. By this means a superior product is insured.

In making use of my apparatus for the purpose of heating granularphosphate rock, which is the main purpose for which the said apparatuswas devised, I found that it was necessary to make use of acylinder B oflight material through which the heat could be readily conveyed, and inmy first apparatus, I depended upon this cylinder to efiect the entireheating. I soon found, however, that while the entrance end of thecylinder did not become over heated in consequence of the heat beingconveyed away bythe evaporation of the volatile matters in the material,that if the latter was maintained in the cylinder B long enough tobecome thoroughly dried, the necessary amount of heat applied to thecylinder 'would soon burn out the rear end from which the materialpassed. This led to the invention of the apparatus above describedwherein a refractory retort is combined with the thin metal cylinder B,which in such case is made only of such size and subjected to such heatas is necessary in order to evaporate the main portion of the volatileconstituents of the material treated, after which the material passesinto the refractory retort, and is therein heated to any extentrequired.

I found other advantages incident to the arrangement described beyondthose which resulted from increasing the durability of the cylinder B,and that was that while the heat necessary for the retort was very greatand the gases passed from the retort furnace in a highly heatedcondition, the said heat was not wasted because such gases wereavailable to heat the cylinder B to the desired extent necessary toeffect the preliminary treatment of the material.

It will be seen that in the construction of apparatus illustrated andabove described the heated gases from the furnace D are not brought incontact with the material to be treated, and therefore there can be nocombinations of the said material with any of the said gases.

I claim- 1. In a calcining apparatus, an externally heated rotatablecylinder of metal with means for feeding material to and from thecylinder, and for heating the same, and a stationary retort ofrefractory material arranged in position to receive the materialdischarged from the cylinder, and means for heating the said retort to ahigh degree of heat, substantially as set forth.

2. The combination of the externally heated rotating cylinder of metal,and means for feeding the material to said cylinder, a stationary retortof refractory material arranged to receive the matter passing from thecylinder, a fire-place for heating the retort and a flue extending fromthe said fire-place beneath the said cylinder, substantially as setforth.

This specification signed and witnessed this 2d day of March, 1893.

WALTER S. PIERCE.

Witnesses:

GEORGE E. CRoUK, W. PELZER.

ICO

